Reimagining Structural Systems: Timber-Concrete Composite Solutions for Modern Buildings

Today’s buildings are expected to deliver more—better performance, greater flexibility, and increased long-term value—prompting a fresh look at the structural systems that support them. Timber concrete composite (TCC) systems offer building owners, developers, and others an opportunity to reduce embodied carbon, improve structural performance, and create spaces that people truly enjoy.

Why Challenge the Status Quo?

Most structural systems are selected based on precedent—what’s worked well in the past. But leaders in the building community must also grasp what will work well in the future, requiring them to challenge themselves and think differently.  

Timber concrete composite (TCC) systems combine mass timber beams or planks with a concrete topping slab. TCC systems can offer a compelling mix of performance, efficiency, and design flexibility. In addition to timber’s well-known environmental benefits—such as low embodied carbon, domestic sourcing, and wildfire mitigation—TCC systems provide significant construction and operational advantages, including the following:

·         Prefabricated timber components can reduce onsite labor, improve safety, and accelerate project timelines.

·         When paired with a concrete topping, the system delivers enhanced fire resistance and acoustic performance, while also offering utility routing and a potential finished floor surface.

·         Structurally connecting the timber and concrete can create a stiffer, efficient system that supports longer spans, reduces floor depth, and enables more open interior spaces and additional building height.

“With mass timber floor systems, there is often an advantage to including a concrete topping, and in some cases this topping layer is required by code. When you structurally interconnect those two materials, you can create a stiffer structural system that takes advantage of the benefits that both materials offer,” says Kirby Beegles, PE, SE, a structural engineer with Martin/Martin.

From Historic Bridges to High-Performance Buildings

TCC systems were first used in Europe after World War II to rehabilitate bridges and buildings when steel was in short supply. Their evolution from retrofit applications to new construction reflects growing interest in hybrid systems that support adaptive reuse, reduce structural depth, and extend building life cycles.

In Canada, TCC systems have been used in projects like Limberlost Place in Toronto and the KF Aerospace Centre in Kelowna, British Columbia. These high-profile examples are helping to normalize the approach, especially for mid-rise and commercial buildings.

Design That Feels Good—Literally

Timber isn’t just good for the planet; it’s good for people. Exposed wood structures support biophilic design—the concept of connecting people with nature to improve health and well-being. As the authors explain in Biophilic Design: The Theory, Science and Practice of Bringing Buildings to Life, incorporating natural materials, such as wood, into architecture “enhances human health, well-being, and performance.”

For developers aiming to create spaces that people love to live and work in, exposed timber offers both aesthetic and psychological benefits. “There’s something about wood that people respond to,” Beegles says.  “It has a smell, a texture, a warmth; it offers a natural variation in its visual pattern that is difficult to achieve with other materials. And it reminds us of nature. People naturally want to touch it.”

Overcoming Challenges, Encouraging Innovation

Of course, TCC isn’t without its challenges. Timber and concrete are often managed by separate trades, and the installation of shear connectors between the materials requires careful coordination. That’s why critical factors include integrated design approaches and involving structural engineers and contractors early.

To support broader TCC-system adoption in the United States, Beegles proposes:

• Full-scale testing of TCC systems using a variety of timber and shear connector components

• Create a U.S.-based design guide similar to the Design Guide for TCC Floors in Canada

• After testing is complete, incorporate TCC methods into the National Design Specification to make these methods accessible to a wide audience

• Produce more design examples, including those that use glulam and other engineered wood products, so practicing engineers can incorporate TCC systems into their design with confidence

These efforts would make TCC systems more available to design teams and more practical for developers who want to integrate low-carbon systems without sacrificing performance or budget.

TCC systems offer more than sustainability—they provide the long spans and structural efficiencies that owners expect from traditional materials like steel and concrete. They also unlock new opportunities for exposed structure, contributing to market differentiation and user experience. As performance standards and client expectations evolve, building owners, architects, and other decision makers who embrace innovative systems, such as TCC, will be positioned to lead.

To learn more about TCC systems, read “Innovations in Timber Concrete Composite Structures,” by Kirby Beegles, PE, SE, which appeared in the January 2025 issue of Structure Magazine.